Bairro Alto (; literally: Upper District) is a central district of the city of Lisbon, the Portuguese capital. Unlike many of the civil parishes of Lisbon, this region can be commonly explained as a loose association of neighbourhoods, with no formal local political authority but social and historical significance to the urban community of Lisbon and of Portugal as a whole.
The bairro or "neighbourhood" resulted from urban expansion in the 16th century, forming outside the walls of the historical city, and is characterized by an almost orthogonal tract (developing from two phases of distinct urbanization).
It is a fundamental quarter of Lisbon, organized into a hierarchical scheme of roads and lanes: the roads, the structural axis, run perpendicular to the river; and the lanes, or secondary axis, cut parallel to the river. However, after 1 August 2009, this restriction was alleviated with an extension to 3:00 a.m., which also included the increase in the number of police officers assigned to the district, to patrol the streets. Around this time, the city council approved a 1.2 million Euro investment project to improve the area's physical appearance and improve security, as well as tackling the excessive graffiti problem.
Geography
thumb|170px|left|The Praça Luís de Camões near the historical gates of Santa Catarina
thumb|170px|left|The Ascensor da Glória connecting between the Praça dos Restauradores and Avenida da Liberdade
Although central to Lisbon, it is normally identified by a different urban nucleus. Bairro Alto is characterized by orthogonal blocks, sometimes rectangular, with a proportion of two lots wide by six or eight lots in length, with many of the length dimensions accompanying the roads, while the shorter dimensions following the lanes. This spatial configuration is not fixed completely within the district.